The present invention relates generally to the automotive chain drive art and, more particularly, to a snap-fit chain guide with locking connector arrangement. In particular, the present invention relates to a novel and unobvious snap-fit chain guide blade that securely and slidably interconnects with a support bracket in a manner that is easy to install, durable and inexpensive.
Chain guides, which for purposes of this document include chain tensioner arms and fixed chain guides, are well known. In a typical arrangement, a blade made of a plastic or other low-friction material is fixedly secured to an underlying support bracket that is, itself, manufactured from metal or a filled plastic material. A wide variety of structures and methods are known for operatively interconnecting a plastic blade to an associated bracket.
One prior method of connecting a plastic blade to a support bracket requires use of an adhesive and/or mechanical fasteners. These methods increase assembly time and costs. Also, the plastic blade can separate from the bracket. In another known arrangement, the plastic blade is molded directly over the support structure of the bracket. This approach is also expensive.
Prior arrangements are known for releasably fitting a plastic blade to a bracket. One example is found in U.S. Pat. No. 5,820,502. In this patent, a plastic blade or lining B is secured to a carrier T with a pivoting snap-fit. However, the disclosed arrangement is limited to an I-beam type bracket or carrier T. Furthermore, the arrangement disclosed in the 5,820,502 patent is not a sliding snap-fit arrangement and, instead, requires that the plastic blade be pivoted or twisted into its operative position. As such, assembly is difficult and blade stress during assembly is increased. Secondly, the required pivoting action limits the different bracket configurations that can be employed, increases the space required for assembly and also increases the risk of improper and incomplete assembly.
In light of the foregoing, it has been deemed desirable to provide a snap-fit chain guide with locking connector arrangement that overcomes the foregoing specifically noted deficiencies and others while providing better overall results.
In accordance with the present invention, a chain guide, such as a fixed chain guide or a tensioner arm, includes a bracket adapted for being secured to an associated engine. The bracket includes a support surface, a leading end and a trailing end spaced from the leading end in a chain movement direction. A guide blade includes a leading end, a trailing end spaced from the leading end in the chain movement direction, a chain guide surface and an inner surface positioned adjacent the support surface of the bracket. The guide blade is selectively movable slidably on the support surface in the chain movement direction and an opposite direction between a first position where the blade is separable from the bracket and a second position where the blade is fixedly secured to the bracket.
One advantage of the present invention resides in the provision of a new and improved snap-fit chain guide with locking connector arrangement.
Another advantage of the present invention resides in the provision of a snap-fit chain guide having a locking connector arrangement wherein the blade is slidably rather than pivotably snap-fit into its operative position.
A further advantage of the present invention resides in the provision of a snap-fit chain guide that exhibits improved connection of the blade to the bracket and that is resistant to undesired movement in the chain travel direction, a direction opposite the chain travel direction and/or in a direction transverse to the chain travel direction.
Still another advantage of the present invention resides in the provision of a snap-fit chain guide that is snap-fit into position by moving the plastic blade in a direction that corresponds to the chain travel direction whereby chain movement cannot dislodge the blade from the bracket.
A further advantage of the present invention is found in the provision of a bracket that includes a support surface that abuts an inner surface of a plastic guide blade or shoe, wherein the support surface of the bracket is defined with a draft angle relative to a parting line and the inner surface of the plastic blade is defined with a corresponding reverse draft angle so that the blade, when loaded, is resistant to movement is a direction transverse to the chain travel direction. Furthermore, defining the inner surface of the plastic blade to have a reverse draft angle that mates with the draft angle of the bracket support surface eliminates a need to machine the support surface of the bracket as would be required if the inner surface of the plastic blade was defined without a reverse draft angle that intimately mates with the draft angle of the bracket support surface.
Other benefits and advantages of the present invention will become apparent to those of ordinary skill in the art to which the invention pertains upon reading this specification.